feat(scripts): Add custom hybrid-architecture thermal-tune & fan control suite (P/E-cores)

[lavacano]

Overview

This pull request introduces a highly optimized, modular thermal tuning and fan control suite under the /scripts/thermal-tune/ directory.

Designed specifically for hybrid-architecture Intel systems (e.g., P-cores + E-cores on the i7-13700HX) and integrated alongside the DAMX daemon, this suite addresses the unique thermal-throttling and latency challenges of running modern gaming laptops on Linux.

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Key Features Included:

1. Dual-Mode Fan Control Daemon (fan-curve-daemon.py)

Provides an advanced two-mode cooling mechanism for shared-heatpipe laptop architectures:

• Independent Mode (Temps < 82°C): CPU and GPU fans track their respective component temperatures independently to minimize noise.
• Coupled Mode (Temps ≥ 82°C): Fans lock together at the max(CPU_temp, GPU_temp) target to balance shared copper heatpipes and avoid one-sided heat saturation.
• EMA Temperature Smoothing: Implements a continuous-time Exponential Moving Average filter ($\tau = 4.0\text{s}$) to smooth out rapid temperature spikes from transient PL2 turbo boosts, eliminating zero-RPM fan bounce.
• Dynamic Polling & Sleep Rates: Scales the polling frequency dynamically based on thermals: 0.5s when hot ($\ge 80^\circ\text{C}$) to protect the silicon from hitting TjMax PROCHOT, and 2.0s under cooler states to save idle power.

2. Advanced Velocity-Form PI Power Governor

Rather than waiting for the CPU to hit hard thermal throttling (TJMax) under load, the governor monitors temperatures in real-time using a continuous-time feedback loop:

• Velocity-Form PI Controller: Uses a Proportional-Integral feedback loop to continuously regulate CPU PL1 based on target convergence ($84^\circ\text{C}$).
• Derivative Damping (Brake): Features a Proportional gain on error velocity ($3.5\text{W}$ per $^\circ\text{C}$ change) acting as an active "damping brake" to counter fast thermal climbs.
• Slew-Rate Limiting: Restricts the maximum change in power limits per poll (e.g., 5W drop/sec, 2.5W recovery/sec) to ensure smooth, stable power transitions.

3. Dynamic EPP Scheduler Asymmetry

Maintains quiet, energy-efficient idle operation without sacrificing responsiveness:

• Under active loads, all cores are set to performance.
• During system idle (CPU < 12%, GPU < 12W for 15s), the daemon prioritizes E-cores by setting P-cores to power (aggressive low-latency sleep) and E-cores to balance_power. This naturally guides the Linux scheduler to run background OS tasks on E-cores first.

4. Hardware Interrupt Affinity Isolation

Freezes out interrupt-induced context switches on gaming threads. In combination with irqbalance, it guides users to ban P-cores (0-15) from interrupt handling, routing major hardware interrupts (GPU, Wi-Fi queues, USB controllers) strictly to E-cores (16-23).

5. Telemetry Web Dashboard (fan-dashboard.html)

A single-file, highly responsive web dashboard using Chart.js to visualize the /var/log/acer_fan_telemetry.csv logs. It highlights coupled zones, power-capped zones, fan speeds, active power limits, and temperature curves in real-time.

6. Hysteresis Auto-Tuner (hysteresis-analyzer.py)

A post-processing diagnostics utility that reads /var/log/acer_fan_telemetry.csv, calculates real-world cooling rates ($^\circ\text{C}/\text{s}$), idle fan bouncing events, and active fan oscillations per hour, and automatically recommends or hot-applies optimized floor/ceiling constraints, zero-RPM silent zone temperatures, and hysteresis parameters to the daemon.

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Folder Structure Added:

scripts/thermal-tune/
├── fan-curve-daemon.py         # Thermal/fan governor daemon (EMA & Velocity PI)
├── hysteresis-analyzer.py      # Telemetry diagnostics & auto-tuner
├── acer-thermal-tune.sh        # RAPL boot script
├── acer-thermal-tune.service   # RAPL systemd unit
├── acer-fan-curve.service      # Daemon systemd unit
├── fan-dashboard.html          # Chart.js telemetry panel
├── 99-custom.rules             # Ananicy rules for P/E-core mapping
├── gaming-thermal.conf         # Vulkan/DXVK performance variables
└── README.md                   # Installation & setup guide